Waveform generator for electrosurgical apparatus

Claim 2

A waveform generator for controlling the output of electrosurgical apparatus, said waveform generator comprising: an MxNxP storage means for storing waveforms where M is the maximum number of different waveforms being stored, N equals the number of bits being output from the storage means at a time with N being greater than one and P is the maximum number of N bits stored for each waveform, said storage means having a plurality of input address lines for selecting each waveform and a plurality of parallel output lines for providing N bits of the waveform at a time, a parallel to serial conversion means loaded by the N bits of the waveform for converting the N bits of the waveform to a single-bit-serial waveform output signal for controlling power output, said output signal having a bit rate N times faster than the rate the storage means is accessed, and control means coupled to said storage means and said conversion means for selecting the next N bits of the waveform from said storage means to be loaded into said conversion means each time a selected number count has been reached.

Claim 3

A waveform generator as set forth in claim 1 wherein said conversion means is a parallel in-serial out shift register.

Claim 4

A waveform generator as set forth in claim 2 wherein the shift register is loaded N bits at a time and shifted out one bit at a time.

Claim 5

A waveform generator as set forth in claim 1 wherein said control means has a counter means with a counter modulus, said counter modulus is set by preloading a count, reaching a full count and counting to zero, an upper bit of said counter means going to zero and reloading the preloaded count.

Claim 6

A waveform generator as set forth in claim 1 wherein there are eight parallel lines into said conversion device.

Claim 7

A waveform generator as set forth in claim 1 wherein there are eight address lines into said storage means.

Claim 8

A waveform generator as set forth in claim 1 wherein said storage means is an EPROM.

Claim 9

A waveform generator as set forth in claim 1 wherein said output signal from said conversion means is applied to a buffer before being coupled to a RF power amplifier of the electrosurgical apparatus.

Claim 10

A waveform generator as set forth in claim 8 wherein the read access time of said storage means is less than N times the output bit stream rate.

Claim 11

A waveform generator as set forth in claim 9 wherein N equals eight.

Claim 12

A waveform generator for controlling the waveform and power output of electrosurgical apparatus, said waveform generator comprising: a clock for providing a REFERENCE FREQUENCY signal, a counter responsive to said REFERENCE FREQUENCY signal that counts to a selected number and then provides a SHIFT REGISTER LOAD signal, an address counter responsive to a N BITS OF THE WAVEFORM signal and to said SHIFT REGISTER LOAD signal, said address counter providing a COUNTER LOAD signal and a SUBADDRESS signal for selecting each N bit word, an MxNxP storage means for storing waveforms where M is the maximum number of different waveforms being stored, N equals the number of bits being output from the storage means at a time and P is the maximum number of N bits stored for each waveform, said storage means having input address lines for selecting each waveform and a plurality of parallel output lines for providing a N bits of the waveform at a time, the access time of said storage means being less than or equal to N times greater than the output of the bit stream, and a parallel to serial shift register loaded by the N bits of the waveform in response to said SHIFT REGISTER LOAD signal, said COUNTER LOAD signal, and said REFERENCE FREQUENCY signal for converting the N bits of the waveform to a SINGLE BIT SERIAL WAVEFORM output signal for controlling power output, said output signal being selected by said SUBADDRESS signal at a speed determined by said REFERENCE FREQUENCY signal.

Claim 13

A waveform generator for controlling the waveform and power output of electrosurgical apparatus, said waveform generator comprising: a clock for providing a REFERENCE FREQUENCY signal, a counter responsive to said REFERENCE FREQUENCY signal that counts to a selected number and then provides a SHIFT REGISTER LOAD signal, an address counter responsive to a N BITS OF THE WAVEFORM signal and to said SHIFT REGISTER LOAD signal, said address counter providing a COUNTER LOAD signal and a SUBADDRESS signal for selecting each N bit word, an MxNxP storage means for storing waveforms where M is the maximum number of different waveforms being stored, N equals the number of bits being output from the storage means at a time and P is the maximum number of N bits stored for each waveform, said storage means having input address lines for selecting each waveform and a plurality of parallel output lines for providing a N bits of the waveform at a time, the access time of said storage means being less than or equal to N times greater than the output of the bit stream, and a parallel to serial shift register loaded by the N bits of the waveform in response to said SHIFT REGISTER LOAD signal, said COUNTER LOAD signal, and said REFERENCE FREQUENCY signal for converting the N bits of the waveform to a SINGLE BIT SERIAL WAVEFORM output signal for controlling power output, said output signal being selected by said SUBADDRESS signal at a speed determined by said REFERENCE FREQUENCY signal.

Claim 14

A waveform generator as set forth in claim 11 wherein said REFERENCE FREQUENCY signal is 20MHz and each bit is 50 nanoseconds in duration.